Glamorgan, I like to keep an eye on it. It is quite a large, leafy lichen; bright green, with pale undersides to the thallus and those tell-tale blackish, raised cephalodia. P. leucophlebia is only to be found in calcareous situations and there is a very similar Peltigera: P. britannica, which is only found in acid situations in uplands. The cephalodia of P. britannica can be easily scratched off, leaving a pale scar, but those of P. leucophlebia cannot be easily removed.
Although the quarries are quite extensive, this lichen only grows in parts of the upper tiers of the middle and upper branches of the quarries, usually amongst slightly taller vegetation on the areas that are less grazed by sheep. I was encouraged to find it to be even more abundant on some areas I haven't checked before.
While there I also came across this local crustose lichen: Gyalecta jenensis, which has distinctive orange centred apothecia. It is often found in growing along cracks and fissures in the vertical faces of the limestone and commonly colonises mosses already growing there.
|Gyalecta jenensis, probably on what was formerly a small clump of|
|Caught in the act of colonising a moss|